I have used several things but am partial to FPPF Killem. That is a real pesticide that will kill those critters and their ancestors. Very reasonably priced. You will have to go thru a few fuel filters before all the carcasses are out of the fuel system. A 16 oz bottle will treat 1280 gallons of fuel and I just checked online and it can be had for right around $25, give or take. This stuff will sanitize the entire fuel system and is a like a nuke explosion on those fuel eating critters. You sure don't need to use it often.

Go to this website http://www.diesel-fuels.com/index.php there is a lot to read but this is the product you need. You will never have a problem with your fuel or filters again. You can email me at gbenkert1@comcast.net

Bio-Bore is the real Mcoy it works best hands down. If you have access to a vacuum pump like one used to change oil in a boat. Attach a longer hose to it and put a 3 ft section of of copper tube at the other end. Stick the copper tube in the tank and and use it like a wand in the low end of the tank to get the creeping crud out. As for how often you should use an algiecide. It's not needed if your going through a tank of fuel say every month or two. If your going through a tank of fuel every day or every other day you won't need it at all. The refinery adds a bio-cide to fuel when it's refined. If you need to buy something such as Bio-Bore get it from a diesel injection shop they have it on the shelf. Stay away from any product that that is not regestered with the EPA as a bio-cide meaning if it dosen't have an EPA reg. Number on the bottle it's not a real Bio-cide. Most people that run diesels don't understand that a diesel injection system by passes a lot of fuel. Fuel is used to cool injection cmponents and passes through your primary and secondary fuel filter many times over. So once you have the creeping crud out it's gone. Unless you let the truck sit for for 6 or 7 months without running it then you may encounter a problem again. I hope this answered your question.